ELECTRIC DRIVE COMPRISING HEAT EXCHANGER SECTION

Abstract

An electric drive provides transmission oil cooling. An oil circuit supplies the transmission with oil. A cooling circuit cools a supply device and/or an electric motor with a coolant. A heat exchanger portion is coupled on one side to the cooling circuit and on the other side to the oil circuit. The supply device is arranged in a supply housing region. The heat exchanger portion forms a wall portion of the supply housing region. An end cover closes the heat exchanger portion. The end cover has at least one functional region, wherein the functional region is designed as a counterpart cooling structure, as an oil sump region and/or as a pump interface for coupling an oil pump.

Claims

1. An electric drive for a vehicle, comprising: at least one electric motor for generating a drive torque; a supply device for supplying the electric motor with electrical energy; a transmission for guiding the drive torque; an oil circuit for supplying the transmission with oil; a cooling circuit for cooling the supply device or the electric motor with a coolant; a heat exchanger portion coupled on a first side to the cooling circuit and on a second side to the oil circuit; a supply housing region, the supply device being arranged in the supply housing region and the heat exchanger portion forming a wall portion of the supply housing region; an end cover closing the heat exchanger portion; wherein the end cover has functional regions, wherein the functional regions are formed at least by a counterpart cooling structure facing the heat exchanger portion and by an oil sump region, wherein the surface of the end cover is enlarged by the counterpart cooling structure in the region of the counterpart cooling structure relative to one of the base surfaces of the end cover on which the counterpart cooling structure is formed on the end cover.

2. The electric drive according to claim 1, wherein the wall portion has an outer cooling structure, wherein the outer cooling structure and the counterpart cooling structure together form an oil guide region, wherein the oil flows through the oil guide region.

3. The electric drive according to claim 2, wherein the counterpart cooling structure is designed as a plurality of ribs, wherein the ribs are oriented transversely to the direction of flow in the oil circuit.

4. The electric drive according to claim 1, wherein the oil sump region is a dry sump region.

5. The electric drive according to claim 1, wherein a further functional region is formed by a pump interface for coupling an oil pump, wherein the pump interface has a mechanical interface for a receiving housing and a fluidic interface for the oil circuit.

6. The electric drive according to claim 1, further comprising a motor housing region for the electric motor, wherein the supply housing region is designed in one piece with the motor housing region.

7. The electric drive according to claim 1, wherein the wall portion has an inner cooling structure, wherein the coolant flows through the inner cooling structure.

8. The electric drive according to claim 7, further comprising a heat-conducting plate for covering the inner cooling structure and for thermal coupling to the supply device.

9. (canceled)

10. The electric drive according to claim 1, wherein the electric drive is an electric axle.

11. The electric drive according to claim 1, further comprising a transmission housing region for the transmission, wherein the supply housing region is designed in one piece with the transmission housing region.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Further features, advantages and effects result from the following description of preferred exemplary embodiments and the attached figures. In the figures:

[0046] FIG. 1 shows a schematic three-dimensional representation of an electric drive for a vehicle;

[0047] FIG. 2 shows a sectional representation of the supply housing region of the electric drive in FIG. 1 in the region of a heat exchanger portion;

[0048] FIG. 3 shows a schematic three-dimensional plan view of an inner wall region of the supply housing region in the region of the heat exchanger portion;

[0049] FIG. 4 shows a schematic three-dimensional plan view of an outer wall region of the supply housing region in the region of the heat exchanger portion;

[0050] FIG. 5 shows a schematic three-dimensional representation of an electric drive;

[0051] FIG. 6 shows a three-dimensional exploded representation of the end cover with adjoining components of the electric drive of FIG. 5;

[0052] FIG. 7 shows a sectional representation through the electric drive of FIG. 5;

[0053] FIG. 8 shows a three-dimensional exploded representation of the end cover with the adjacent supply housing region of the electric drive from FIG. 5.

DETAILED DESCRIPTION

[0054] FIG. 1 shows, in a schematic three-dimensional representation, an electric drive 1 for a vehicle, wherein the electric drive is designed as an electric axle. The electric drive 1 has a housing 2, wherein the housing 2 can be functionally divided into a motor housing region 3, a gear housing region 4 and a supply housing region 5. The housing 2 is designed as a die-cast aluminum housing and is realized in multiple parts. In this exemplary embodiment, the gear housing region 4 and the supply housing region 5 form a common component, which is designed as a die-cast part made of an aluminum alloy.

[0055] An electric motor 6, which provides a drive torque for the electric drive 1, is arranged in the motor housing region 3. A transmission 7 is arranged in the gear housing region 4, wherein the transmission 7 converts the drive torque and distributes it to two output shafts, not shown. A supply device 8, which provides the electrical energy for the electric motor 6, is arranged in the supply housing region 5. In particular, the supply device 8 comprises power electronics with shift elements and/or power modules for providing the electrical energy for the electric motor 6.

[0056] The transmission 7 is cooled and lubricated with oil via an oil circuit 9, wherein the cooling circuit 9 has one or more oil pumps 10 for conveying the oil. The oil circuit 9 is only shown in a highly schematic manner; the components of the oil circuit 9 can also be distributed differently.

[0057] The electric motor 6 and/or the supply device 8 are cooled with a coolant via a cooling circuit 11. The cooling circuit 11 optionally has a coolant pump 12.

[0058] The supply housing region 5 has a heat exchanger portion 13 which, from a functional point of view, transfers thermal energy from the material flow of the oil from the oil circuit 9 to the material flow of the coolant from the cooling circuit 11 or in the opposite direction. In the first exemplary embodiment, the heat exchanger portion 13 is arranged under an end cover 14 or is also formed by this, as will be explained below.

[0059] FIG. 2 shows a schematic section through the heat exchanger portion 13, wherein it is evident that the heat exchanger portion 13 is formed by a wall portion of the supply housing region 5. In particular, the heat exchanger portion 13 is designed in one piece with the supply housing region 5.

[0060] On an outer wall region 15, the heat exchanger portion 13 has outer cooling structures 16, which are molded into the wall portion in the outer wall region 15. The outer cooling structures 16 are fluidically closed by the end cover 14, so that the oil of the oil circuit 9 can flow through the outer cooling volume 23 formed thereby directly and/or without loss.

[0061] On an inner wall region 17, the heat exchanger portion 13 has inner cooling structures 18, which are molded into the wall portion in the inner wall region 17. The inner cooling structures 18 are fluidically closed by a heat-conducting plate 19, shown only schematically, or another heat-conducting body, so that the coolant of the cooling circuit 11 can flow through the resulting inner cooling volume 24 without loss. The supply device 8 is arranged on the heat-conducting plate 19 or the heat-conducting body, so that waste heat generated during operation can be dissipated into the cooling circuit 11 via the heat-conducting plate 19 or the heat-conducting body.

[0062] Between the inner cooling structures 18 and the outer cooling structures 16 there is a residual wall section of the supply housing region 5, which implements a fluidic separation but a thermal coupling between the cooling structures 18 and 16. In particular, the remaining wall portion is formed from the aluminum alloy of the supply housing region 5.

[0063] FIG. 3 shows a schematic three-dimensional top view of the inner wall region 17, wherein it can be seen that the inner cooling structures 18 are arranged in a flat region and are formed by three sub-portions through which the arrows flow in parallel and which have cooling pins to enlarge the surface 21a. Furthermore, sealing elements 20 can be seen which fluidically seal the inner cooling volume 24 through which the flow is flowing with the heat-conducting plate 19 or the heat-conducting body.

[0064] FIG. 4 shows a schematic three-dimensional top view of the outer wall region 15, wherein it can be seen that the outer cooling structures 16 are also arranged in a flat region and are formed by two sub-portions which are flowed through in series and which have cooling pins 21b to enlarge the surface. A circumferential flange seal 22 can also be seen, which fluidically seals the outer cooling volume 23 with the end cover 14.

[0065] As indicated by a dotted line in FIG. 2, the end cover 14 can have a counterpart cooling structure 28, wherein the counterpart cooling structure 28 protrudes into the outer cooling volume 23 and enlarges the surface of the end cover 14 compared to a flat configuration. In this way, heat can be supplied or removed through the end cover 14.

[0066] FIG. 5 shows an electric drive 1 as a second exemplary embodiment in a schematic three-dimensional representation. The electric drive 1 has a housing 2, wherein the housing 2 has a portion of a motor housing region 3 for coupling an electric motor, not shown, and a gear housing region 4 for receiving a transmission 7. Furthermore, the housing 2 has a supply housing region 5 for receiving a supply device, not shown. In particular, the electric drive 1 of FIG. 5 and the following forms a variant of the electric drive 1 of the first exemplary embodiment. Reference is therefore made to the first exemplary embodiment for the description. In particular, the first and second exemplary embodiments differ in terms of the end cover 14 and the arrangement of the oil pump 10.

[0067] The end cover 14 is designed as a metal part, in particular as a cast part, for example as an aluminum die-cast part. Three functional regions are integrated in the end cover 14, namely the already mentioned counterpart cooling structure 28, an oil sump region 29 and a pump interface 30.

[0068] The end cover 14 extends under the heat exchanger portion 13 and/or the supply housing region 5 as well as an intermediate region between the motor housing region 3 and the transmission housing region 4. Furthermore, the end cover 14 with the pump interface 30 protrudes laterally beyond the base of the housing 2, so that the pump interface 30 is arranged next to the housing 2.

[0069] FIG. 6 shows the end cover 14 in an individual representation, wherein components for the oil pump 10 are graphically supplemented in an exploded illustration. A receiving housing 31 is fastened to the end cover 14 at the pump interface 30 by means of a screw connection, wherein the oil pump 10 is inserted into the receiving housing 31. The pump interface 30 thus forms a mechanical interface for the oil pump 10.

[0070] The oil sump region 29 is designed as a recess so that it provides an oil sump region volume of, for example, 0.5 L. The oil sump region 29 is fluidically connected to the pump interface 30 so that the oil pump 10 can pump oil out of the oil sump region 29. In particular, the oil circuit 9 runs from the oil sump region 29 via the pump interface 30 and the oil pump 10 into the heat exchanger portion 13.

[0071] The counterpart cooling structure 28 is arranged higher than the oil sump region 29 in the installed position of the end cover 14 and has a plurality of ribs 32, wherein the ribs as can best be seen in FIG. 8—are oriented transversely to the oil circuit 9 in the heat exchanger portion 13. The large number of ribs 32 increases the surface area of the end cover 14.

[0072] FIG. 7 shows the region of the heat exchanger portion 13 in a schematic longitudinal section through the electric drive 1. On the right-hand side, in the transition region between the supply housing region 5 and the motor housing region 3, the oil sump region 29 can be seen. Below the supply housing region 5, in particular in the region of the heat exchanger portion 13, the counterpart cooling structure 28 can be seen in section. In the wall portion of the supply housing region 5 on the outer wall region 15, outer cooling structures 16 are molded, which engage in spaces between the ribs 32 of the counterpart cooling structure 28, so that the outer cooling structures 16 are interlocked with the counterpart cooling structure 28. An oil guide region 33, which forms a portion of the oil circuit 9, is formed in the outer cooling volume 23 between the outer cooling structures 16 and the counterpart cooling structure 28. The oil guide region 33 runs alternately between lower-lying portions, which are formed by the floor between the ribs 32, and higher-lying portions, which are formed by the ceiling between the outer cooling structures 16. As a result, the portion of the oil circuit 9 formed by the oil guide region 33 is designed to be lengthened, so that a thermal connection is improved.

[0073] Inner cooling structures 18 are arranged, in particular integrally formed, on the inner wall region 17 and form a portion of the inner cooling volume 24 and thus of the cooling circuit 11. As in the previous exemplary embodiment, the inner cooling volume 24 is covered, for example, by a heat-conducting plate 19, not shown, which is in thermal contact with the supply device 8, not shown.

[0074] Optionally, a reservoir (not shown) can be provided below the counterpart cooling structures 28, which is fluidically connected to the oil sump region 29. In this way, a larger amount of oil can be provided in the oil circuit 9. The reservoir can be integrated into the end cover 14. The oil sump region 29 and possibly the reservoir form a low-pressure region for the oil. Fluidically, a high-pressure region for the oil in the oil circuit 9 follows the oil pump 10 in the heat exchanger portion 13. Following the heat exchanger portion 13, the oil circuit 9 runs in the transmission housing portion 4 to the transmission 7.

[0075] In FIG. 8, the end cover 14 is shown again together with a partially cut end region of the electric drive 1 or the supply housing region 5. In this representation, the oil circuit 9 and the cooling circuit 11 are shown schematically, wherein it can be seen that the two circuits 8, 11 are oriented in opposite directions. This has the advantage that the greatest temperature differences always coincide. In the case of a cold start, the cold oil meets the coolant at the beginning of the heat exchanger portion 13, which has already flowed through the heat exchanger portion 13 and is therefore already warmed up by the supply device 8. This achieves a maximum heating output for the oil. In the operating state, the oil can give off heat to the cooling circuit 11.

LIST OF REFERENCE SYMBOLS

[0076] 1 Electric drive [0077] 2 Housing [0078] 3 Motor housing region [0079] 4 Transmission housing region [0080] 5 Supply housing region [0081] 6 Electric motor [0082] 7 Transmission [0083] 8 Supply device [0084] 9 Oil circuit [0085] 10 Oil pump [0086] 11 Cooling circuit [0087] 12 Coolant pump [0088] 13 Heat exchanger portion [0089] 14 End cover [0090] 15 Outer wall region [0091] 16 Outer cooling structures [0092] 17 Inner wall region [0093] 18 Inner cooling structures [0094] 19 Heat-conducting plate [0095] 20 Sealing elements [0096] 21a, b Cooling pins [0097] 22 Flange seal [0098] 23 Outer cooling volume [0099] 24 Inner cooling volume [0100] 25 Empty [0101] 26 Wall portion [0102] 27 Housing wall [0103] 28 Counterpart cooling structure [0104] 29 Oil sump region [0105] 30 Pump interface [0106] 31 Receiving housing [0107] 32 Ribs